The invention relates to an apparatus for treating body tissue with ultrasound having a generator and means for transmitting ultrasound into the tissue as well as a hollow probe for removing the treated tissue.
Such an apparatus is described for example in the brochure xe2x80x9cSONOTOM 110, Ultraschallaspiratorxe2x80x9d, 9/95, of the company Berchthold GmbH and Co, Medizin-Elektronik, Tuttlingen, Germany.
Ultrasound is not only used for diagnostic purposes for viewing body structures of varying density, it is also used for therapeutic purposes. Ultrasound is either applied externally to the skin or directly within the body at the tissue to be treated by means of corresponding laparoscopic instruments, optionally with endoscopic control.
As a result of the ultrasound treatment, the tissue is heated and caused to denaturate, the so-called (thermo) coagulation. Apart from heat development, ultrasound has a mechanical effect in the form of so-called cavitation. Sound waves propagate in a medium as periodic density fluctuations of the medium. A volume element of the medium is alternately compressed (higher pressure) and expanded (lower pressure). The lower pressure in a liquid, for example in the cytoplasma of the cells or in the tissue fluid can cause vapor bubble formation, which destroys the cells and tissue.
Such an ultrasound treatment is suited for disintegration or dissolution of soft tissue, for example fat tissue. Generally, ultrasound waves in the region of 26 kHz are employed. The coagulated and/or disintegrated tissue is suctioned into a tube-shaped hollow probe, where in addition a washing means for flushing purposes is normally also provided. The flushing fluid is passed through a hollow space between the probe and an outer shaft. The flushing fluid mixed with the cell or tissue residue is suctioned off through the hollow probe.
Such ultrasound treatments are particularly employed for the destruction of tumorous tissue. It is especially applied in liver surgery, because one can skeletonize, i.e. only tissue can be removed from an organ, for example the liver, without cutting or destroying blood vessels of the organ.
However, since ultrasound can only destroy extremely soft tissue in loose cell structures, an ultrasound treatment of more solid tissue and tumors or other hard tissue is not sufficient. Sharper cutting devices, scalpels, etc. are employed which additionally complicates the operation.
Other medical instruments such as surgical knives or scalpels employ ultrasound, which are set into vibration by means of ultrasound. Such an xe2x80x9cultrasound drivenxe2x80x9d surgical knife for laparoscopic application is disclosed in WO 93/14708. A knife is slidably arranged in the interior of a shaft, from which it is drawn out for the operation. Ultrasound energy is transmitted directly and exclusively to the knife, which is then excited to undergo vibration. A therapeutic application of ultrasound for tissue disintegration is not possible with this surgical cutting device. In addition, it is not possible to remove the cut tissue parts from the operation field. Furthermore, the device is limited to diameters larger than 1 cm.
A further development of this surgical knife is disclosed in U.S. Pat. No. 5,346,502, which is similar in that ultrasound is applied to the surgical knife for vibration. In this case, an outer diameter of the shaft of 5 mm is achieved. This instrument however is extremely complicated in manufacture, because the shaft is made of PTFE and must be subjected to several expansion and contraction processes. In addition, it is not possible to apply ultrasound to destroy soft tissue with this knife.
The German patent DE 40 42 435 C2 discloses an ultrasound treatment apparatus having a hand piece with an ultrasound oscillator and a plurality of probes connectable to the hand piece. Thus an ultrasound apparatus is provided, which is inexpensive with respect to purchase and maintenance costs and at the same time can be used for the most different applications.
The European patent application EP 0 384 672 A2 discloses an ultrasound probe by which the distal suction opening is variable in its form and size to achieve an optimal suction force for withdrawing treated tissue.
The European patent application EP 0 238 667 A1 discloses an ultrasound instrument whose distal end is formed in spoon shape. A central flushing channel supplies fluid to the spoonlike distal end.
The U.S. Pat. No. 5,188,102 describes a surgical knife driven by ultrasound to undergo vibration. A central flushing channel is provided by which a flushing fluid is fed to the distal end, particularly at an angle of 5xc2x0 to 90xc2x0 with respect to the cutting plane.
The U.S. Pat. No. 5,047,043 also describes a surgical knife driven by ultrasound, by which an endoscope is inserted to observe the distal end visually.
The European patent application EP 0 695 535 A1 describes a gripping instrument driven by ultrasound, which can grasp the tissue removed by ultrasound.
The U.S. Pat. No. 5,322,055 describes an apparatus driven by ultrasound, which is suitable for cutting and coagulating. A clamping device provided at the distal end, where the tissue to be coagulated is held between a moveable mouth portion and a stationary mouth portion.
In view of the above background art, an object of the present invention is to provide an improved apparatus for therapeutic treatment of body tissue with ultrasound, which apart from removing soft tissue structures also makes it possible to remove harder tissue structures with constructively simple means.
According to the present invention, an apparatus of the abovementioned type is provided, which has a cutting blade in the region of the distal end of the hollow probe and a grasping means having a first and a second jaw. In conventional ultrasound devices for therapeutic treatment, the hollow probe serves only to draw off and discharge the coagulated and fluidized cell and tissue components, optionally to further inject a flushing fluid into the operation area and to remove it again.
By providing a cutting blade at the distal end of the probe, i.e. at the probe tip which is open for suction purposes, a multifunctional medical instrument is provided in simple manner. The soft tissue components can be disintegrated and suctioned off and at the same time, more rigid tissue portions which are insensitive to ultrasound, can be cut out and also removed. The effect is exploited, that the end of the probe located in the operation area can be excited to undergo vibration, also in therapeutic ultrasound applications. The vibrating cutting blade has excellent cutting properties, even when the blade itself is comparatively blunt.
The function of destroying tissue in the present apparatus is further enhanced by the heat generation of the therapeutic ultrasound waves. Thus it is possible with a single instrument to simultaneously disintegrate tissue through ultrasound, to cut and/or scrape off with the cutting blade and also to coagulate, whereby the continuously loosened cell or tissue pieces are removed from the operation area.
It will be understood that the cutting blade can be used to separate hard or soft tissue components, for example to separate fat tissue from subcutaneous tissue. Under these circumstances, the apparatus of the present invention is used as a cutting and suction apparatus.
The provisions of the grasping means has the advantage that the present apparatus has two further functions, which are often needed in operations where tissue is to be removed. For example, vessels, nerves, etc. can be grasped and such tissue structures can be cut. When cutting arteries, it is advantageous that the heat generation caused by ultrasound also causes coagulation and therefore helps stop the bleeding.
The grasping and cutting function is necessary especially when solid tissue components are to be removed or to be cut and then removed. When the ultrasound is turned off, the present apparatus becomes a pinching or clamping means with the two jaws arranged at the distal end of the probe, with which blood vessels can be held fixed without cutting them.
The present invention thus unifies several functions, which in the mentioned applications are necessary directly in the operation area and it also saves the operator from frequent changes of surgical devices. Such operations are therefore substantially easier and faster to perform as has been previously possible. The multifunctionality of the apparatus is achieved with very simple means, namely by providing the distal end of the hollow probe with a cutting blade and with two jaws for grasping and/or cutting.
In a preferred embodiment, the cutting blade is an integral part of the probe wall. This has the advantage that the blade can be manufactured simply, namely simultaneously with the hollow probe. In addition, high reliability is achieved with this measure, as means for securing the cutting blade to the distal end of the probe are not required.
In a particularly preferred embodiment, the cutting blade is formed as a projection from the probe wall. The cutting blade can be flat or curved, it can be tampered or broadened depending on the desired application.
The formation of the cutting blade as a projection has the considerable advantage that the present apparatus receives an additional function, namely it can also be used as a spattle. The blade, which can be relatively blunt, can then serve as a spattle surface for scraping off tissue when the ultrasound source is turned off. The scraped off tissue is located on the flat projection in a position directly before the opening in the hollow probe and can therefore be directly suctioned off.
When the ultrasound generator is turned on, the projection begins to vibrate and has the effect of a sharp cutting blade. Preferably the cutting blade is exposed and can readily access the tissue to be cut.
In a further embodiment of the present invention, the first jaw of the grasping and cutting means is formed by the cutting blade. This has the advantage of being constructively simple, since only the second jaw needs to be additionally provided at the distal end of the probe.
In a further embodiment, the second jaw of the grasping and/or cutting means is slidable along the longitudinal axis of the probe, consists of a super elastic material and is bent backward of the first jaw in the state of being extended out of the hollow probe. When being drawn into the hollow probe, it moves toward the first jaw.
The shifting of the jaw along the longitudinal axis can be accomplished for example with an actuator element, which is operated from the proximal side of the apparatus. The super-elastic material can be for example Nitinol, a nickel-titanium alloy, which is a so-called xe2x80x9cmemory materialxe2x80x9d. The material has the property that after being deformed it always returns to its original form. This has the advantage that the grasping and cutting means is simple in manufacture and in operation, without the necessity of joints, pivots or the like. The curvature of the second, slidable jaw can be oval or flattened or can also comprise complicated bendings or curvatures, depending on the desired application.
In a further embodiment of the present invention, a guide and glide element for the second jaw is provided in the interior of the hollow probe. This has the advantage that the sliding of the jaw and therefore the opening and closing of the jaw for releasing or gripping is performed without friction. The guide and glide element is preferably made of Teflon. This has the further advantage that a possible welding of the second jaw to the probe, which under some circumstances could occur when the ultrasound is activated and generates heat, is reliably avoided.
In a further preferred embodiment, the second jaw of the grasping and cutting means is spread apart from the first jaw by pivotal movement. By pivoting about a transverse axis, the second jaw is thus spread apart from the first jaw in an open position of the grasping and/or cutting means or it is flapped shut again in the direction of the first jaw. It is also possible to turn the second jaw completely back from the distal opening of the probe, so that it does not interfere with the cutting function with the cutting blade or with the suctioning off of tissue residue.
In a further preferred embodiment of the present invention, the probe comprises an outer shaft in which the second jaw is pivotally secured. This has the advantage that the outer shaft can be used for securing or journaling the second jaw. The pivot action can be achieved for example with a rod or cable, which can also be provided within the outer shaft wall. Alternatively, the second jaw can be journaled such that a shifting of the outer shaft causes the rotation of the second jaw. In addition, the outer shaft advantageously protects the hollow probe from mechanical loads.
A flushing fluid is supplied. in the space between the outer shaft and the hollow probe. By providing the outer shaft, it is also possible to withdraw the cutting blade entirely into the shaft, whereby undesired tissue damage is avoided, for example when introducing the probe into the body.
In a further embodiment of the present invention, the outer shaft comprises an upper half and a lower half, which are shiftable relative to one another at a separation line along the longitudinal axis of the probe. A shifting of the half on which the second jaw is anchored causes a pivotal movement of the second jaw. This has the advantage that the relative shifting of the outer shaft halves exerts the necessary tension on the second jaw to rotate it relative to the first jaw.
In a further preferred embodiment of the present invention, the grasping and/or cutting means comprises a tube having a projection and being disposed in the interior of the hollow probe. The probe and the tube are rotatable relative to one another and the projection interacts with the cutting blade of the probe. This has the advantage that the apparatus is formed as a rotary pincher or forceps. By rotating the probe and the inner tube relative to one another either by rotating the inner tube or the outer tube or both tubes together, tissue sections can be brought between the projection and the cutting blade and either be grasped or even be cut, so that the device can act as rotary grasping forceps or as rotary cutting forceps.
With this geometry, a particularly slender structure is formed so that no jaws or tongs which extend to the side beyond the circumference of the outer shaft are present. This embodiment is particularly.employed when relatively small pieces are to be grasped or cut.
In a further embodiment of the present invention, the projection of the inner tube is placed in a rotary position to lie closely adjacent to the cutting blade, so that both projections act as a compact element. This has the advantage that in this rotary position one can work with the probe as if no grasping means were present, since the two tubes are rotated with respect to one another so that their projections work as one structure. In this angular position, this compact structure can be used either as a cutting blade and/or as a spattle.
In a further embodiment, the axial edges of the projections are blunt. This has the advantage that the pincher or forceps are designed to perform only grasping and cutting does not take place.
In a further embodiment of the invention, the axial edges of the projections are sharp. In this embodiment, the apparatus is designed to work as a cutting forceps. It is also possible that both embodiments be combined, i.e. a sharp edge and a blunt edge are formed, so that in one rotation direction a grasping effect is achieved and in the other rotational direction a cutting effect is achieved.
In a further embodiment, the hollow probe can be supplied with high frequency current (HF). This allows a further function of the present apparatus, namely its use for HF coagulation, for example to rapidly and efficiently close off strongly bleeding vessels by applying HF current. It will be understood that a high frequency generator will be necessary to produce the HF power. The HF power is transmitted through the probe to the proximal cutting blade and causes a denaturation of the tissue contacting the cutting blade.
It will be understood that the above-mentioned features and those to be discussed below are not only applicable in the given combinations, but may be present in other combinations or taken alone without departing from the scope of the present invention.